How do I check if a TCP port is open online?

Enter your server's IP address or domain followed by a colon and the port number (e.g. 1.1.1.1:80 or example.com:443) and run a TCP check. The tool attempts a TCP handshake from 65+ global nodes and reports whether each connection succeeded, was refused, or timed out.

What is the difference between a port being refused versus timing out?

A refused connection (TCP RST) means the port is actively closed — the server replied to reject the connection. A timeout means no reply was received at all, which typically indicates a firewall is silently dropping packets before they reach the server or application.

Which TCP ports can I test?

Any valid TCP port from 1 to 65535. Common examples include port 80 (HTTP), 443 (HTTPS), 22 (SSH), 25 (SMTP), 3306 (MySQL), 5432 (PostgreSQL), and 3389 (RDP). No login or special permissions required — the check only verifies whether the TCP handshake completes.

My port is open locally but fails from external nodes — why?

If a port works locally but fails from external nodes, something between the internet and your server is blocking it — commonly a cloud security group, iptables rule, upstream ISP filter, or geoblocking policy. Running the check from multiple regions helps identify whether the block is global or specific to certain countries or ASNs.

Rapport pour google.com:80

Info Ping HTTP TCP UDP MTR DNS

Vérifier TCP google.com:80

Vérifié le Oct 23, 2026 05:36:18 UTC |

| Revérifier |

Emplacement	Résultat	Temps	Adresse IP
Australia, Sydney	Connected	0.0 ms	142.250.183.46
Bosnia and Herzegovina, Novi Travnik	Connected	23.0 ms	192.178.24.14
Bulgaria, Sofia	Connected	1.0 ms	192.178.24.78
Canada, Montreal	Connected	8.0 ms	74.125.197.101
Switzerland, Bern	Connected	1.0 ms	142.250.180.14
Switzerland, Zurich	Connected	12.0 ms	142.251.110.138
China, Hohhot	ERROR	-	142.251.188.139
Cyprus, Larnaca	Connected	9.0 ms	142.250.75.78
Germany, Nuernberg	Connected	5.0 ms	142.251.127.102
Germany, Frankfurt am Main	Connected	0.0 ms	142.251.14.113
Germany, Frankfurt am Main	Connected	0.0 ms	142.250.154.139
Germany, Frankfurt am Main	Connected	2.0 ms	192.178.183.138
Germany, Koblenz	Connected	16.0 ms	142.251.20.139
Germany, Frankfurt am Main	Connected	5.0 ms	142.251.127.102
Denmark, Glostrup Municipality	Connected	25.0 ms	172.217.19.238
Spain, Bilbao	Connected	38.0 ms	142.251.14.138
Spain, Barcelona	Connected	22.0 ms	172.217.20.46
Finland, Helsinki	Connected	6.0 ms	64.233.164.102
Finland, Helsinki	Connected	28.0 ms	142.250.181.238
France, Gravelines	Connected	13.0 ms	142.251.14.102
France, Paris	Connected	10.0 ms	172.217.22.46
United Kingdom, London	Connected	9.0 ms	142.250.129.102
Hong Kong, Hong Kong	Connected	1.0 ms	172.217.23.238
Croatia, Zagreb	Connected	24.0 ms	142.251.20.102
Hungary, Budapest	Connected	44.0 ms	142.251.14.138
Israel, Petach Tikwa	Connected	2.0 ms	142.250.75.46
Israel, Netanja	Connected	2.0 ms	142.250.75.46
Iran, Tehran	Connected	82.0 ms	142.251.38.142
Iran, Tehran	Connected	82.0 ms	142.251.38.142
Iceland, Reykjavik (Miðborg)	Connected	23.0 ms	172.253.116.113
Italy, Como	Connected	0.0 ms	142.251.209.46
Japan, Tokyo	Connected	2.0 ms	192.178.226.100
South Korea, Seoul	Connected	40.0 ms	142.251.118.102
Kazakhstan, Almaty	Connected	93.0 ms	172.217.19.238
Lithuania, Pilaite	Connected	38.0 ms	142.251.98.139
Latvia, Riga	Connected	61.0 ms	192.178.183.102
Netherlands, Amsterdam	Connected	1.0 ms	142.251.39.142
Netherlands, Amsterdam	Connected	7.0 ms	142.251.39.142
Netherlands, Amsterdam	Connected	1.0 ms	192.178.24.142
Netherlands, Amsterdam	Connected	0.0 ms	142.251.142.206
Netherlands, Eygelshoven	Connected	4.0 ms	142.251.209.238
Norway, Oslo	Connected	38.0 ms	142.251.38.110
Poland, Warsaw	Connected	16.0 ms	142.251.98.101
Romania, Bacău	Connected	40.0 ms	142.251.13.102
Romania, Bucharest	Connected	8.0 ms	142.251.208.110
Serbia, Belgrade	Connected	11.0 ms	192.178.24.78
Russia, Moscow	Connected	21.0 ms	172.217.19.238
Singapore, Singapore	Connected	5.0 ms	172.253.118.101
Tor, Onion	Connected	561.0 ms	google.com
Tor, Onion	Connected	123.0 ms	google.com
Tor, Onion	Connected	678.0 ms	google.com
Turkey, Istanbul	Connected	9.0 ms	192.178.25.238
Ukraine, Khmelnytskyi	Connected	11.0 ms	142.251.98.102
United States, Dallas	Connected	1.0 ms	142.250.113.101
United States, Los Angeles	Connected	30.0 ms	142.251.32.174
United States, Houston	Connected	7.0 ms	173.194.208.139
United States, Miami	Connected	1.0 ms	142.251.215.46
South Africa, Johannesburg	Connected	2.0 ms	142.251.47.206